(a) Field of the Invention
The present invention relates to an electric nerve stimulation and more particularly to a transcutaneous nerve stimulating device and method for suppression of organic pain and other functional disorders of the nervous system, without noxious sensation and substantially free from the nerve cell adaptation phenomenon.
(b) Description of Prior Art
Electrotherapy of pain and motor disorders was made possible with the development of modern electronics. The most important single factor that opens a new era in electrotherapy was the publication by Melzack and Wall in 1965 of their work on gate theory of pain from which it is evidently shown that in order to suppress pain it was necessary and sufficient to electrically stimulate the thicker strong myelinated fibers which are responsible for the transmission of touch, vibration and pressure. According to the authors of the gate theory such stimulation would result in inhibition of the transmission of impulses in the thinner unmyelinated fibers carrying noxious information.
In the majority of prior art devices, transcutaneous stimulators were proposed to suppress organic pain by generating pulse through the skin to stimulate the peripheral nerve fibers, whereas the noxious sensations were eliminated by varying the pulse amplitude, pulse duration and/or pulse repetition rate, thereby placing very restrictive parameters on the operation of such devices. However, this treatment did not eliminate the adaptation phenomenon of receptors and nerve cells to sensor impulses. In this respect, U.S. Pat. No. 3,817,254 to Maurer proposes to introduce a variation in the pulse repetition rate to overcome the adaptation phenomenon by providing a ram generator as an input to a pulse generator.